Knife-grinding machine



(No Model.) 2 Sheets-Sheet 1.

W. D. GRAVES, Jr. KNIFE GRINDING MACHINE.

No. 425,781. Patented Apr. 15, 1890.

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W. D. GRAVES, Jr. KNIFE GRINDING MACHINE.

No. 425.781. Patented Apr. 15, 1890.

IN VE N TOR A TTOl-PNE YS I UNITED STATES PATENT OFFICE.

\VILLIAM D. GRAVES, JR, OF PRESQUE ISLE, MAINE.

KNIFE-GRINDING MACHINE.

SIECIFICATION forming part of Letters Patent No. 425,781, dated April 15, 1890.

I Application filed February 1 1890. Serial No. 338,919. (No model.)

To all whom it may concern:

Be it known that I, WILLIAM D. GRAVES, ,In, of Presque Isle, in the county of Aroostook and State of Maine, have invented a new and useful Improvement in Knife-Grinding Machines, of which the following is a full, clear, and exact description.

My invention relates to improvements in knife-grinding machines, and has for its obect to provide a simple, compact, automatically-acting device, whereby straightedged knives for various machines may be ground to a bevel edge rapidly and accurately.-

To this end my invention consists in the construction and combination of parts, as is hereinafter described and claimed.

The essential features embodied in the invention consist of a supporting frame, whereon a longitudinally-sliding knife-carrying table is mounted, which receives reciprocatory motion from gearing that automatically reverses the longitudinal movement of the table, as will be more specifically described.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure 1 is a front elevation of the machine. Fig. 2 is an end elevation of the same, the knife-supporting. table being broken away, and a portion of a grindstone shown with the knife bearing thereon; and Fig. 3 is a transverse sectional elevation of the same, taken on the line 3 3 in Fig. 1.

A represents the frame of the machine, and consists of two housing-pieces a, vertically erected on the base-plate a, a proper space intervening said housings for the reception of other parts.

On the upper portion of the housings a ax ially-coincident boxes 00 are formed, in which a cylindrical shaft 12 is supported to rock and slide, and below the shaft 1) grooves are formed in the boxes a for loosely supporting a rack b, which is held in place longitudinally by the hub ends of the knifesupporting frame herein after described.

A skeleton knife-supporting frame B, consisting of the platen c and arms a, is secured upon the shaft b by mounting the enlarged hub ends 0 of the arms a on the terminals of the shaft, set-screws being provided, which afford means for attaching the frame B to the shaft. v

The boxes (I, that are formed in the upright housings a at a suitable distance above the base-plate a, have their true horizontal bores in alignment for the revoluble support of the driving-shaft O, that projects outside of the frame at one side and has a pulley e secured on said projecting portion. Upon the shaft 0 two transverse rock-arms f of equal dimensions are mounted, said arms being transversely perforated of a diametrical size to tit and rock upon the shaft near their longitudinal centers, which will afford laterally-proj ecting portions of equal length for each arm f. At equal distances from the center holes in the rock-arms f said arms are perforated for reception of the ends of the short journalshafts g, that are each secured to the rockarms, thereby affording a stable rocking frame,

and on these journal-shafts g worm-sleeves g and pinions g integral therewith or secured thereto, are loosely mounted.

Upon the driving-shaft O a pinion g is se: cured, so as to align with the pinions g which pinion is of such proportionate diameter that it will mesh on opposite sides with each of said pinions g and revolve them in different directions.

Between the pinion g and the rock-arm f which is farthest removed therefrom a spiral spring h is placed on the shaft 0 and compressed, so that the expansion of the spring longitudinally upon the shaft will force the rock-arm it presses upon in frictional contact with the adjacent true face of the collar 2', which is secured to the shaft 0, and consequently revolves with it.

The worm-threads on the sleeves g are pitched in opposite directions, and the distance from the axis of the shaftC to the outer peripheral edge of each worm is such with regard to the position of the teeth on the rackbar I) that said worms may be successively caused to engage the rack-teeth by a halfrevolntion of the rock-arms f on their support.

In the upper part of each flange piece or lateral brace a formed on'the upright hous ings a, open guide-slots are produced, which grind it to a true bevel edge.

are downwardly and inwardly inclined and receive thecomposite tappet-barm and loosely support it to move endwise. The tappet-bar 'm consists of a straight rectangular metallic bar having a'length proportioned to the capacity of the machine, and on its side two similar shifting-dogs m are secured, their adjacent ends, which are imposed upon the side of the bar, being removably attached 1o thereto by screws or other means. The 'free end portions of the shifting-dogs m are given equal return-bends toward each other, which locates their locking-toes m in the same horizontal plane in such relative position that the lugs n, which project from the outer faces of .the rock-arms f at opposite ends thereof, will either of them engage an opposing toe m when the parts are moved to cause such alternate abutment of the toes and lugs, as will be further explained.

Movable abutment-collars o o are mounted on the body of the sliding rack-bar 1) outside of the supporting-boxes a and are also designed to limit the longitudinal movement of the rack-bar b by their impingement on the tappet-bar m.

In operation the knife-blank D, which is to be bevel-ground on the stone or emery-wheel D, is clamped or temporarily bolted upon 0 the platen c, which will thus sustain the blank with its edge projected to engage the face of the grinding-wheel D. Below the platen c a vertical post E is erected, which is adjustable for height, so that its upper end 0 willengage 5 the platen and arrest the grinding action in an obvious manner. Rotation of the drivingshaft C will cause the rock-arms f of the bracket-frame, which has contact with the collar 2', to move around on the shaft 0 until 46 a Worm-sleeve g is aligned with the rack-bar b and the worm-thread thereon meshes with the rack-teeth, as shown in Fig. 1, the proper alignment of the rack and worm being deter mined by the abutment of the moving lug n 5 with the locking-toe m of the tappet-bar m.

The rotation of the worm-sleeve g by the pinions g g will longitudinally move the rackbar b until the collar 0 thereon, which is approaching the end of the tappet-bar m, abuts 50 against it, shifting said bar sufficiently to release the interlocking connection of the lug n with the toe m The rock-arms will now be moved together and cause the ot er wormsleeve to mesh its worm-thread with the rack 5 5 bar 12.

site abutment-collar 0 is brought into contact with the tappet-bar the motion is again reversed. It is to be understood that the collars 0 0 are so adjusted to the length of the knife to be ground that the latter will be made to traverse the stone or emery-wheel D from one end to the other of the knife and Furthermore,

the interlocking of the toe on oneend of the tappet-bar with an opposinglug is maintained until the knife-blank has been made to en gage the-stonethroughout its length, when the reversedmovement of the blank 1s effected in the manner hereinbefore explained.

By adjustment of the abutment collars 0 0 toward the boxes on of the frame the reciprocal travel of the knife-carrying frame B may be shortened to suit knives which do not require the full longitudinal movement of the device to sharpen the edges of the scope of my invention; hence I do not desire to limit the same to the precise forms herein shown.

Having thus described my inventiomwhat I claim as new, and desire to secure by Letters Patent, is' l 1. In a knife-grinding machine, the combination, with a knife-carryin g table supported to slide with a longitudinally reciprocable rack-bar, of opp ositely-threaded worm-sleeves adapted to successively engage the rack-bar and reciprocate it and means for rocking the worm-sleeves toward the rack-bar alternately and revolving them oppositely, substantially as set forth.

2. In a knife-grinding machine, the combination, with an upright frame and a knifecarrying frame engaged by a longitudinallyreciprocable rack bar, of revoluble wormsleeves having oppositely-pitched threads and supported to rock on a driving-shaft, so as to alternately engage the rack-bar teeth, a driving-shaft, and means for revolving it, substantially as set forth.

3. In a knife-grinding machine, the combination, with a frame, a sliding rack-bar there- 'on, a knife-carrying frame on a rocking shaft,

and a longitudinally-movable tappet-bar on said frame, of a driving-shaft revolubly supported on said frame,revoluble worm-sleeves threaded oppositely and supported to rock on the driving-shaft alternately to engage the rack-bar, gearing for rotating the worm-sleeves in opposite directions, means for rotating the driving-shaft, and a device, substantially as shown, for successivelyretaining the wormsleeves in gear with the rack-bar, substantially as set forth.

4. In a knife-grinding machine, the combination,with an upright frame,a sliding rackbar on said frame, a knife-carrying frame adjustably secured on a rocking and sliding shaft, and atappet-bar mounted on said frame, of oppositely-threaded worm-sleeves and a driving-shaft on which said wormsleeves are mounted to rock, said worm-sleeves being adapted to be alternately thrown into engagement with the rack-bar by the conjunctive sliding movement of the rack-bar and rocking movement of the worm-sleeves, substantially as set forth.

5. In a knife-grinding machine, the combi-' nation, with an upright frame having spaced housings and a base, a rack-bar supported to reciprocate in said frame, a knife-carrying frame adj ustably secured on a shaft journaled on the frame, and a tappet-bar mounted to slide on said frame, of a driving-shaft revolubly supported on the housings of the upright frame and carrying a pulley, rock-arms loosely mounted on the driving shaft, oppositelypitohed Worm-sleeves revolubly supported by 

